Flip chip mounting body, flip chip mounting method and flip chip mounting apparatus

ABSTRACT

The flip chip mounted body of the present invention includes: a circuit board ( 213 ) having a plurality of connection terminals ( 211 ); a semiconductor chip ( 206 ) having a plurality of electrode terminals ( 207 ) that are disposed opposing the connection terminals ( 211 ); and a porous sheet ( 205 ) having a box shape that is provided on an opposite side of a formation surface of the electrode terminal ( 207 ) of the semiconductor chip ( 206 ), is folded on an outer periphery of the semiconductor chip ( 206 ) on the formation surface side of the electrode terminal ( 207 ) and is in contact with the circuit board ( 213 ), wherein the connection terminal ( 211 ) of the circuit board ( 213 ) and the electrode terminal ( 207 ) of the semiconductor chip ( 206 ) are connected electrically via a solder layer ( 215 ), and the circuit board ( 213 ) and the semiconductor chip ( 206 ) are fixed by a resin ( 217 ). Thereby, the flip chip mounted body with excellent productivity and reliability that can mount the semiconductor chip on the circuit board, and a method and an apparatus for mounting the flip chip mounted body are provided.

This application is a division of U.S. Ser. No. 11/909,856, filed Sep.27, 2007, which is a U.S. National Stage of PCT/JP2006/305004, filedMar. 14, 2006, which applications are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a flip chip mounting method formounting a semiconductor chip on a circuit board. In particular, thepresent invention relates to a flip chip mounted body that is adaptableto a semiconductor chip with a narrower pitch and has high productivityand excellent reliability of connection, a method for mounting the same,and a flip chip mounted apparatus.

BACKGROUND ART

In recent years, with a trend toward a higher density and a higherdegree of integration for a semiconductor integrated circuit(hereinafter, abbreviated as a “semiconductor”) chip used for electronicequipment, the number of pins of electrode terminals of a semiconductorchip has been increased and the pitch thereof has been decreasedrapidly. For mounting these semiconductor chips on circuit boards, flipchip mounting is used widely in order to decrease a wiring delay.

In this flip chip mounting, solder bumps generally are formed onelectrode terminals of the semiconductor chip, which then are joined toconnection terminals formed on the circuit board with these solder bumpsat one time.

However, in order to mount a next-generation semiconductor chip havingmore than 5,000 electrode terminals on a circuit board, it is necessaryto form solder bumps that correspond to a narrow pitch of 100 μm orless, but it is difficult to adapt to it with a current technique forforming solder bumps.

Moreover, since it is necessary to form a large number of solder bumpsthat correspond to the number of the electrode terminals, theproductivity has to be raised by shortening a mounting cycle for eachchip, in order to achieve a cost reduction.

Similarly, in the semiconductor chip, the increase in the number of theelectrode terminals has brought about a transition fromperipheral-disposed electrode terminals to area-disposed electrodeterminals.

Moreover, due to the demands for a higher density and a higher degree ofintegration, a semiconductor process is expected to develop from 90 nmto 65 nm and further to 45 nm. As a result, the wiring becomes evenfiner, and the formation of the solder bumps on the area-disposedelectrode terminals and the flip chip mounting of the semiconductor chipbecome difficult.

Thus, there is a demand for a flip chip mounting method that isadaptable to a decrease in thickness and an increase in density due tothe future development of the semiconductor process.

Conventionally, as a technique for forming solder bumps, plating, screenprinting and the like have been developed. The plating is suitable for anarrow pitch, but has a problem in productivity due to its complicatedprocesses. On the other hand, the screen printing has excellentproductivity, but is not suitable for narrowing a pitch because of theuse of a mask.

In the light of the problems described above, several techniques forforming solder bumps selectively on electrode terminals of asemiconductor chip or a circuit board have been developed recently.These techniques not only are suitable for forming fine solder bumps butalso have excellent productivity because they can form the solder bumpsall at one time, and attract attention as techniques that are adaptableto the mounting of the next-generation semiconductor chip on the circuitboard.

One of these techniques is called a solder paste method. In thistechnique, a solder paste, which is a mixture of solder particles andflux, is applied solidly onto a circuit board whose surface is providedwith electrode terminals, and the circuit board is heated so as to meltthe solder particles, whereby solder bumps are formed selectively on theelectrode terminals that have a high wettability (see Patent document 1,for example).

Moreover, in a technique called a super solder method, a paste-likecomposition (chemical reaction deposition-type solder) that contains anorganic acid lead salt and metal tin as main components is appliedsolidly onto a circuit board on which electrode terminals are formed,and the circuit board is heated so as to cause a substitution reactionbetween Pb and Sn, thereby depositing a Pb/Sn alloy selectively on theelectrode terminals of the board (see Patent document 2, for example).

A conventional flip chip mounting further requires a process ofinjecting a resin called an underfill between the semiconductor chip andthe circuit board in order to fix the semiconductor chip on the circuitboard, after mounting the semiconductor chip on the circuit board onwhich solder bumps are formed. Thereby, there also have been problems ofan increase of the number of steps and an decrease of a yield.

Then, as a method for establishing an electric connection betweenopposed electrode terminals of the semiconductor chip and the circuitboard and fixing the semiconductor chip onto the circuit board both atthe same time, a flip chip mounting technique using an anisotropicelectrically conductive material has been developed. In this technique,by supplying a thermosetting resin containing electrically conductiveparticles between the circuit board and the semiconductor chip, and thenheating the thermosetting resin while applying pressure to thesemiconductor chip at the same time, it is possible to establish theelectric connection between the electrode terminals of the semiconductorchip and the circuit board and fix the semiconductor chip to the circuitboard at the same time (for example, see Patent document 3).

However, in both of the solder paste method described in Patent document1 and the super solder method described in Patent document 2, since thepaste-like composition simply is supplied onto the circuit board byapplication, local variations in thickness and concentration occur,resulting in variations in the solder deposition amount for individualelectrode terminals. Consequently, it is not possible to achieve solderbumps with uniform heights. Also, in these methods, since the paste-likecomposition is supplied by application onto the circuit board whosesurface is provided with the electrode terminals, namely, withprojections or depressions, a sufficient amount of solder cannot besupplied onto the electrode terminals serving as the projections, makingit difficult to achieve a desired solder bump height necessary for theflip chip mounting.

Moreover, in the flip chip mounting method described in Patent document3, there are many problems in productivity and reliability that are tobe solved as described below.

Firstly, since the electric conduction between the electrode terminalsis obtained by mechanical contact via the electrically conductiveparticles, it is difficult to achieve a stable conductive state.Secondarily, since a distance varies depending on an amount of theelectrically conductive particles that are present between the electrodeterminals of the semiconductor chip and the circuit board, the electricconnection is unstable. Thirdly, in the heating process for curing thethermosetting resin, the electrically conductive particles arescattered, which causes a decrease of a yield due to a short circuitgenerated thereby. Fourthly, because of a structure where a connectionpart between the semiconductor chip and the circuit board is exposed andsinks into moisture or the like, and a life span and reliability of thecircuit board deteriorate.

Patent document 1: JP 2000-94179 A

Patent document 2: JP1 (1989)-157796 A

Patent document 3: JP2000-332055 A

DISCLOSURE OF INVENTION

In order to solve the above-described problems, it is an object of thepresent invention to provide a flip chip mounted body with excellentproductivity and reliability, which can mount a next-generationsemiconductor chip having more than 5,000 electrode terminals on acircuit board, a flip chip mounting method and a flip chip mountedapparatus.

A flip chip mounted body of the present invention includes: a circuitboard having a plurality of connection terminals; a semiconductor chiphaving a plurality of electrode terminals that are disposed opposing theconnection terminals; and a porous sheet having a box shape that isprovided on an opposite side of a formation surface of the electrodeterminal of the semiconductor chip, is folded on an outer periphery ofthe semiconductor chip on the formation surface side of the electrodeterminal and is in contact with the circuit board, wherein theconnection terminal of the circuit board and the electrode terminal ofthe semiconductor chip are connected electrically via a solder layer,and the circuit board and the semiconductor chip are fixed by a resin.

A flip chip mounting method of the present invention is a flip chipmounting method for disposing a semiconductor chip having a plurality ofelectrode terminals so as to oppose a circuit board having a pluralityof connection terminals and connecting the connection terminal of thecircuit board and the electrode terminal of the semiconductor chipelectrically, the flip chip mounting method including: adhering thesemiconductor chip to a porous sheet and subsequently deforming aperiphery of the semiconductor chip; applying a solder resin compositionthat contains solder particles, a convection additive and a resin asmain components onto the circuit board or the semiconductor chip;positioning so as to dispose the porous sheet on the circuit board;heating the solder resin composition to a temperature at which thesolder particles are melted so as to generate gas by boiling ordecomposition of the convection additive; and connecting the connectionterminal and the electrode terminal electrically by allowing the meltedsolder particles to flow in the resin composition so as to self-assembleand grow the solder particles before the gas is released, passes throughthe porous sheet and is scattered.

Another flip chip mounting method of the present invention is a flipchip mounting method for disposing a semiconductor chip having aplurality of electrode terminals so as oppose a circuit board having aplurality of connection terminals and connecting the connection terminalof the circuit board and the electrode terminal of the semiconductorchip electrically, the flip chip mounting method including: deforming aporous sheet so as to have a box shape covering the semiconductor chip;adhering the semiconductor chip to an inside bottom part of the poroussheet having a box shape; applying a solder resin composition thatcontains solder particles, a convection additive and a resin as maincomponents onto the circuit board or the semiconductor chip; positioningso as to dispose the porous sheet on the circuit board; heating theresin composition to a temperature at which the solder particles aremelted so as to generate gas by boiling or decomposition of theconvection additive; and connecting the connection terminal and theelectrode terminal electrically by allowing the melted solder particlesto flow in the resin composition so as to self-assemble and grow thesolder particles before the gas is released, passes through the poroussheet and is scattered.

Still another flip chip mounting method of the present invention is aflip chip mounting method for disposing a semiconductor chip having aplurality of electrode terminals so as to oppose a circuit board havinga plurality of connection terminals and connecting the connectionterminal of the circuit board and the electrode terminal of thesemiconductor chip electrically, the flip chip mounting methodincluding: adhering the semiconductor chip to a porous sheet; applying asolder resin composition that contains solder particles, a convectionadditive and a resin as main components to the board or thesemiconductor chip; positioning so as to dispose the porous sheet on thecircuit board; deforming the porous sheet; heating the resin compositionto a temperature at which the solder particles are melted so as togenerate gas by boiling or decomposition of the convection additive; andconnecting the connection terminal and the electrode terminalelectrically by allowing the melted solder particles to flow in theresin composition so as to self-assemble and grow the solder particlesbefore the gas is released, passes through the porous sheet and isscattered.

Still another flip chip mounting method of the present invention is aflip chip mounting method for disposing a semiconductor chip having aplurality of electrode terminals so as to oppose a circuit board havinga plurality of connection terminals and connecting the connectionterminal of the circuit board and the electrode terminal of thesemiconductor chip electrically, the flip chip mounting methodincluding; applying a solder resin composition that contains solderparticles, a convection additive and a resin as main components to thecircuit board or the semiconductor chip; positioning so as to disposethe semiconductor chip on the circuit board; applying an adhesive to thesemiconductor chip so as to adhere the porous sheet to the semiconductorchip; deforming the porous sheet; heating the resin composition to atemperature at which the solder particles are melted so as to generategas by boiling or decomposition of the convection additive; andconnecting the connection terminal and the electrode terminalelectrically by allowing the melted solder particles to flow in theresin composition so as to self-assemble and grow the melted solderparticles before the gas is released, passes through the porous sheetand is scattered.

A flip chip mounted apparatus of the present invention is a flip chipmounting apparatus for flip-chip-mounting a semiconductor chip on acircuit board, the flip chip mounting apparatus including: a fixingmember that fixes the semiconductor chip to a porous sheet; a deformingmember for deforming a periphery of the porous sheet along acircumference of the semiconductor chip; an applying member for applyinga solder resin composition that contains solder particles, a convectionadditive and a resin as main components onto the circuit board or thesemiconductor chip; a positioning member for positioning thesemiconductor chip by holding the porous sheet on the circuit board; anda heating member for melting the solder particles of the resincomposition.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1A to 1C are cross-sectional views showing a basic processmechanism of a flip chip mounting method according to one example of thepresent invention.

FIG. 2 is a cross-sectional view showing a flip chip mounted bodyaccording to Embodiment 1 of the present invention.

FIGS. 3A to 3E are cross-sectional process views showing the flip chipmounted body and a flip chip mounting method according to Embodiment 1of the present invention.

FIGS. 4A to 4D are cross-sectional process views schematicallyexplaining a flip chip mounted body and a flip chip mounting methodaccording to Embodiment 2 of the present invention.

FIGS. 5A to 5D are cross-sectional process views schematicallyexplaining a flip chip mounted body and a flip chip mounting methodaccording to Embodiment 3 of the present invention.

FIGS. 6A to 6D are cross-sectional process views schematicallyexplaining a flip chip mounted body and a flip chip mounting methodaccording to Embodiment 4 of the present invention.

DESCRIPTION OF THE INVENTION

In the mounted body of the present invention, a connection terminal of acircuit board and an electrode terminal of a semiconductor chip areelectrically connected via a solder layer. This solder layer is formedon a solder connection body by assembly of solder particles. This solderlayer is formed by heating a solder resin paste containing the solderparticles, a resin and a convection additive so as to boil theconvection additive and cause convection of the resin, assembling thesolder particles, and connecting the connection terminal and theelectrode terminal. That is, by the heating, the convection additive inthe paste state is boiled, and the solder particles are assembledaccording to this boiling. If the solder particles also are melted atthis time, the solder particles are self-assembled to the connectionterminal and the electrode terminal that have high wettability, and canbe formed into the solder layer. On an opposite side of a formationsurface of the electrode terminal of the semiconductor chip, a poroussheet having a box shape that is folded on the formation surface side ofthe electrode terminal on an outer periphery of the semiconductor chip,and is in contact with the circuit board is provided. This porous sheetallows the gasified convection additive to escape toward the outsidewhen forming the solder layer by assembling the solder particles betweenthe connection terminal of the circuit board and the electrode terminalof the semiconductor chip, and thus is used for maintaining a gapbetween the connection terminal of the circuit board and thesemiconductor chip, and the positions thereof.

The porous sheet may have a box shape that covers the semiconductor chipand has a brim whose peripheral edge protrudes near its opening.

Further, the porous sheet may have a hole that connects a front side anda rear side.

Further, the porous sheet may be made of a material that has airpermeability such as a thermoplastic resin, a thermosetting resin, anonwoven fabric or a foam metal.

Further, the hole of the porous sheet may be closed by a resin.

Further, a part around the porous sheet that is in contact with thecircuit board may be contacted with a resin.

According to such a configuration, the flip chip mounted body that hasexcellent reliability of the connection or the like and a mechanicalstrength can be achieved.

In the method of the present invention, a process for deforming theporous sheet may include heating.

Further, in the process for deforming a periphery of the porous sheet,the porous sheet may be processed so as to cover the semiconductor chipand have a box shape, and a peripheral edge of an opening of the poroussheet having the box shape is in contact with the circuit board, so thatthe semiconductor chip and the circuit board may be disposed at apredetermined interval.

Further, the porous sheet may have a box shape that covers thesemiconductor chip and has the brim whose peripheral edge protrudes nearthe opening thereof.

According to these methods, since the interval between the electrodeterminal of the semiconductor chip and the connection terminal of thecircuit board may be maintained to have an appropriate distance, adisconnection and a high resistance connection are not likely to occurbecause of the uniform connection between the electrode terminal and theconnection terminal, thereby improving a yield.

Further, the porous sheet may have a hole that connects a front side anda rear side.

Further, the porous sheet may be made of a material that has airpermeability such as a thermoplastic resin, a thermosetting resin, anonwoven fabric or a foam metal.

Further, the resin contained in the resin composition may penetrate theporous sheet by the heating of the circuit board, close the hole in theporous sheet, and be cured after completion of the heating of thecircuit board, so that moisture permeability may be decreased orinhibited.

Further, the part around the porous sheet that is in contact with thecircuit board may be contacted with the resin contained in the resincomposition.

According to these methods, deterioration of the semiconductor chipcaused by moisture and water can be reduced, so that the reliability andthe life span can be improved. Further, since the connection of thesemiconductor chip can be secured, the circuit board that has excellentvibration resistance and shock resistance can be achieved.

Further, an electrode may be provided so as to surround the connectionterminal of the circuit board.

Further, the electrode that is provided so as to surround the connectionterminal of the circuit board may be formed to be positioned inside theporous sheet that has the box shape, and a dummy bump may be formed bythe process of heating the circuit board.

Further, the electrode on which the dummy bump is formed by the heatingprocess may prevent passing of the solder particles in the resincomposition that is applied between the circuit board and thesemiconductor chip, and may allow the resin to pass through.

According to these methods, the solder particles in the resincomposition that is applied between the circuit board and thesemiconductor chip are prevented from scattering and flowing out to theoutside by the electrode on which the dummy bump is formed. And, bypreventing the contact, the short circuit and the like with the adjacentsemiconductor chip by the scattered solder particles, the reliabilityand the yield can be improved.

Moreover, since the solder particles are self-assembled to the electrodeon which the dummy bump is formed, the passing of the solder particlesbetween the electrodes is limited. On the other hand, passing of theresin is possible. Thus, an appropriate amount of the resin in the resincomposition flows out from the electrode on which the dummy bump isformed, and sinks between a circumference edge of the porous sheet andthe circuit board, so that the outflow stops. As a result, the poroussheet and the circuit board can be fixed reliably by the resin that hasbeen sunk.

Moreover, the flip chip mounted apparatus of the present invention is aflip chip mounting apparatus for flip-chip-mounting a semiconductor chipon a circuit board, the flip chip mounting apparatus including: a fixingmember that fixes the semiconductor chip to a porous sheet; a deformingmember for deforming a periphery of the porous sheet along acircumference of the semiconductor chip; an applying member for applyinga resin composition that contains solder particles, a convectionadditive and a resin as main components onto the circuit board or thesemiconductor chip; a positioning member for positioning thesemiconductor chip by holding the porous sheet on the circuit board; anda heating member for melting the solder particles of the resincomposition. According to this apparatus, the flip chip mounted bodyhaving excellent reliability can be manufactured at a low cost and highproductivity.

Incidentally, in the present invention, a main component means 80 wt %or more, and preferably 90 wt % or more.

In the above description, a melting point of the solder particlespreferably ranges between 100° C. and 300° C. inclusive.

Moreover, an average particle diameter of the solder particlespreferably ranges from 1 μm to 50 μm.

Further, a temperature at which the solder resin paste is heatedpreferably is the melting point of the solder or more.

The solder resin paste includes a resin, solder particles and aconvection additive that is boiled when the resin is heated. As theresin, a thermosetting resin (for example, an epoxy resin) is used, andas the solder particles, Pb-free solder particles are used. As theconvection additive, a solvent (for example, an organic solvent) can beused, and examples thereof include isopropyl alcohol (boiling point:82.4° C.), butyl acetate (boiling point: 125° C. to 126° C.), butylcarbitol (diethylene glycol monobutyl ether, boiling point: 201.9° C.),ethylene glycol (boiling point: 197.6° C.) and the like. The content ofthe convection additive in the resin is not limited particularly, andpreferably ranges from 0.1 wt % to 20 wt %.

Moreover, the “convection” of the convection additive means convectionas a form of a motion, and may be any form of motion that provideskinetic energy to the solder particles that are dispersed in the resinby the motion of the boiled convection additive in the resin, andpromotes the transfer of the solder particles. Incidentally, as theconvection additive, not only a convection additive that is boiled byitself and generates convection, but also a convection additive thatgenerates gas (H₂O, CO₂, N₂ or the like) by the heating of the resin canbe used. Examples thereof include a compound containing hydrated crystalmaterials, a compound that is decomposed by heat and a foaming agent.

Arbitrary solder particles can be selected to be used. Examples thereoflisted in Table 1 can be used. Materials listed in Table 1 as examplesmay be used alone or in combination appropriately. Moreover, it ispreferable to use a material whose melting point is lower than a curingtemperature of the thermosetting resin as the solder particles, becausethe resin is heated and cured after the resin flows and isself-assembled, so that electrical connection and sealing by the resincan be achieved.

TABLE 1 Composition of Melting point solder particle (solidus) (° C.)Sn—58Bi 139 Sn—37Pb 183 Sn—9Zn 199 Sn—3.0Ag—0.5Cu 217 Sn—3.5Ag 221Sn—0.7Cu 228 12Sn—2.0Ag—10Sb—Pb 240

A melting point of the solder particles preferably ranges from 100° C.to 300° C., and more preferably ranges from 139° C. to 240° C., as shownin Table 1. If the melting point is less than 100° C., a problem indurability tends to occur. If the melting point is more than 300° C., itbecomes difficult to select the resin.

An average particle diameter of the solder particles preferably rangesfrom 1 μm to 30 μm, and more preferably ranges from 5 μm to 20 μm. Whenthe average particle diameter is less than 1 μm, it becomes difficult tomelt the solder particles due to the surface oxidation, and theformation of the electric connectors tends to take too much time. Whenthe average particle diameter is more than 30 μm, it becomes difficultto obtain the electric connectors due to the sedimentation of the solderparticles. Note here that the average particle diameter can be measuredusing a commercially available particle size distribution analyzer. Forexample, the average particle diameter can be measured using a laserdiffraction particle size analyzer (LA920) available from HORIBA, Ltd.,a laser diffraction particle size analyzer (SALD2100) available fromShimadzu Corporation, or the like.

Next, the resin will be described. Typical examples of the resininclude: thermosetting resins such as epoxy resin, phenol resin,silicone resin, diallyl phthalate resin, furan resin, and melamineresin; thermoplastic resins such as polyester elastomer, fluororesin,polyimide resin, polyamide resin, and aramid resin; photocurable(ultraviolet curable) resins; and mixtures thereof in combination.

The mixing ratio by volume of the solder particles and the resinpreferably is in the following range: conductive particles:resin=50 to5:95 to 50, more preferably, solder particles:resin=40 to 10:90 to 60.It is preferable to use the solder particles and the resin after theyhave been mixed together homogenously. For example, 20 vol % of thesolder particles and 80 vol % of the epoxy resin are mixed homogenouslyby a kneading machine, and the thus-obtained mixture is used. Note herethat a paste in which the solder particles remain dispersed may be used,or the rein formed into a sheet form may be used.

Furthermore, in preferred examples of the present invention, lead-freesolder alloy particles whose melting point ranges from 200° C. to 250°C. can be used as the solder particles, for example. When the resin is athermosetting resin, it is preferable that the curing temperature of theresin is higher than the melting point of the solder. With thisconfiguration, it is possible to cure the resin during the steps offorming electric connectors and forming metal bumps, thus allowing theoperation process to be shortened.

According to the flip chip mounted body and the method for mounting theflip chip mounted body of the present invention, the mounting methodthat provides a reliable connection between the semiconductor chip andthe circuit board can be achieved, and the flip chip mounted body thathas improved weather resistance against humidity or the like forincreasing the life span of the circuit board and has excellentreliability can be achieved. Further, since a connection state betweenthe electrode terminal and the connection terminal can be uniform,increased yield and improved production efficiency can be achieved.

FIGS. 1A to 1C are views showing a mechanism of basic processes in oneexample of the present invention. Firstly, as shown in FIG. 1A, a resincomposition 15 containing solder particles 12, a convection additive 13and a resin 14 is supplied onto a circuit board 10 on which a pluralityof connection terminals 11 are formed.

Next, as shown in FIG. 1B, the circuit board 10 and a semiconductor chip20 are in touch with each other through the intervening the resincomposition 15 that is supplied between the circuit board 10 and thesemiconductor chip 20. At this time, the semiconductor chip 20 having aplurality of electrode terminals 21 is disposed opposing the circuitboard 10 having the plurality of the connection terminals 11. And, inthis state, the circuit board 10 is heated so as to melt the resincomposition 15. Here, the circuit board 10 is heated at a temperaturehigher than a melting point of the solder particles 12. The meltedsolder particles 12 are bound to one another in the melted resincomposition 15, and are self-assembled between the connection terminal11 and the electrode terminal 21 that have high wettability so as toform a solder connector 22, as shown in FIG. 1C.

Then, the resin 14 is cured, so that the semiconductor chip 20 is fixedto the circuit board 10.

This method is characterized in that the resin composition 15 containingthe solder particles 12 further contains a convection additive 13 thatis boiled to a temperature at which the solder particles 12 are melted.That is, at the temperature at which the solder particles 12 are melted,the convection additive 13 contained in the resin composition 15 isboiled. Then, the convection of the boiled convection additive 13 occursin the resin composition 14, thereby promoting the transfer of themelted solder particles 12 that float in the resin composition 14. As aresult, the melted solder particles 12 that have been grown uniformlyare self-assembled between the connection terminal 11 of the circuitboard 10 and the electrode terminal 21 of the semiconductor chip 20 thathave the high wettability, and the connection terminal 11 and theelectrode terminal 21 are connected electrically via the uniform andfine solder connector 22.

That is, the above-described method is intended to add a means fortransferring the melted solder particles forcefully by allowing theresin composition containing the solder particles further to contain theconvection additive. Incidentally, the convection additive may be asolvent that is boiled or evaporated by heat, and hardly remains in theresin composition after the completion of the processes.

In the light of the similar technical standpoint, the present inventionaims to achieve a new flip chip mounting method that is more precise andhas higher reliability. And, by carrying out the present invention, acircuit board that is flip-chip-mounted can be manufactured at asignificantly high yield.

Embodiment of the present invention will be described below in detailwith reference to the drawings. It should be noted that the drawings areshown being expanded arbitrarily for easier recognition.

Embodiment 1

FIG. 2 is a cross-sectional view showing a flip chip mounted bodyaccording to Embodiment 1 of the present invention. In FIG. 2, a flipchip mounted body 200 according to Embodiment 1 of the present inventionhas a configuration where a plurality of connection terminals 211 formedon a circuit board 213 and a semiconductor chip 206 having a pluralityof electrode terminals 207 that are disposed opposing the connectionterminals 211 are connected electrically via a solder layer 215. Then, aporous sheet 205 that is provided on an opposite side of a formationsurface of the electrode terminal 207 of the semiconductor chip 206 isfolded to have a box shape 209 on the formation surface side of theelectrode terminal 207 on an outer periphery of the semiconductor chip206, and is formed so as to cover the semiconductor chip 206, whereby anend surface of the box shape 209 is in contact with the circuit board213. Further, in a space formed by the circuit board 213 and the poroussheet 205 with the box-shape, the semiconductor chip 206 and the circuitboard 213 are fixed by the solder layer 215 that connects the connectionterminal 211 and the electrode terminal 207 electrically, and by a resin217 that covers the surroundings thereof, thereby constituting the flipchip mounted body 200.

The flip chip mounted body and a flip chip mounting method according toEmbodiment 1 of the present invention will be described below withreference to FIGS. 3A to 3E.

FIGS. 3A to 3E are cross-sectional process views explaining the flipchip mounted body and the flip chip mounting method according toEmbodiment 1 of the present invention.

Firstly, as shown in FIG. 3A, an upper mold 201 is provided with asuction pipe 202 that can achieve vacuum aspiration by exhausting airvia an exhaust pipe 204 and a suction path 203 constituted of smallholes. And, the porous sheet 205 is made of, for example, athermosetting resin or a thermoplastic resin that is not dissolved intoa solvent, which is a material having holes that allows gas to paththrough between a front side and a rear side. Example thereof includemicroporous PET (polyethylene terephthalate) and PTFE(polytetrafluoroethylene) that have air permeability. Incidentally, as amaterial of the porous sheet 205, not only a resin but also materialsthat have air permeability such as a nonwoven fabric and a foam metalmay be used.

And, on the porous sheet 205, the semiconductor chip 206 that has aplurality of the electrode terminals 207 on a lower surface of thesemiconductor chip 206 is adhered.

Next, as shown in FIG. 3B, the porous sheet 205 on which thesemiconductor chip 206 is attached is disposed between the upper mold201 and a lower mold 208, whereby only an end part of the porous sheet205 is folded, for example, along a periphery (outer periphery) of thesemiconductor chip 206 by applying a pressure, thereby deforming theporous sheet 205 into the box shape 209. At this time, it is preferableto heat the upper mold 201 and the lower mold 208 at a temperatureappropriate for the deformation (for example, 120° C. in the case ofPET), because the form of the porous sheet 205 can be deformed moreeasily.

Next, as shown in FIG. 3C, the lower mold 208 is detached, and isreplaced with a position of the circuit board 213 on which the uppermold 201 is to be mounted in a state of drawing the porous sheet 205 andthe semiconductor chip 206. At this time, the connection terminal 211formed on the surface of the circuit board 213 and the electrodeterminal 207 of the semiconductor chip 206 are positioned by imagerecognition such as by a camera. Further, at a position where thesemiconductor chip 206 is to be mounted at least on the circuit board213, the resin composition 212 containing solder particles, a convectionadditive and a resin is applied by an applying member such as adispenser. Moreover, around a part where the circuit board 213 does notmake a short circuit with the connection terminal 211, for example, anelectrode 210 that forms a dummy bump for preventing the scattering ofthe solder particles is provided. And, the electrode 210 for forming thedummy bump is provided on the circuit board 213 in a range surrounded bythe box shape 209 of the porous sheet 205.

Next, as shown in FIG. 3D, the semiconductor chip 206 and the circuitboard 213 are brought into contact with each other through theintervening the resin composition 212. Herein, the electrode terminal207 of the semiconductor chip 206 and the connection terminal 211 of thecircuit board 213 oppose each other so as to have a predeterminedinterval by the box shape 209 of the porous sheet 205. The predeterminedinterval means a spacing so that at least the electrode terminal of thesemiconductor chip and the connection terminal of the circuit board arenot in contact with each other, and the melted solder particles canintervene.

And, at least the circuit board 213 side is heated at a temperatureranging from 220° C. to 250° C., for example, at which the solderparticles are melted by using a heating member, for example, a heater.

By this heating, the convection additive (not illustrated) in the resincomposition 212 that is applied on the circuit board 213 is boiled orevaporated so as to be gasified, and the solder particles (notillustrated) are changed into melted solder particles. Then, in aprocess in which the gas passes through the holes in the porous sheet205 that is folded to have the box shape 209 and goes out through theexhaust pipe 204 toward an outside, the melted solder particles in theresin composition 212 are transferred by the convection.

Further, the melted solder particles that have been transferred areself-assembled between the electrode terminal 207 of the semiconductorchip 206 and the connection terminal 211 of the circuit board 213 thatare disposed opposing each other and have high wettability, and aregrown.

A specific example will be given below. A mixture obtained byhomogenously mixing 85 parts by volume of a bisphenol F type epoxy resin(Japan Epoxy Resins Co., Ltd., Epikote 806, including a hardeningagent), 15 parts by volume of SnAgCu powder with a particle diameterranging from 10 to 25 μm (average particle diameter: 17 μm), and 3 partsby weight of isopropyl alcohol as a convection additive was used as thesolder resin paste. This solder resin paste was injected between thecircuit board 213 and the surface of the semiconductor chip 206 using adispenser. The temperature was raised from the room temperature (25° C.)to 250° C., and was maintained for 30 seconds. The solder resin pastethen was cooled and the cross section thereof was observed, whichrevealed the state shown in FIG. 3E. As the porous sheet, a porous filmof PTFE with a thickness of about 30 μm was used.

As shown in FIG. 3E, a solder layer 215 that electrically connects theelectrode terminal 207 and the connection terminal 211 is formed, andthe upper mold 201 is detached, so that the flip chip mounted body 250is formed. Moreover, the melted solder particles are self-assembled andgrown also on the electrode 210 for forming the dummy bump so as to formthe dummy bump 214. By the formation of this dummy bump 214, the meltedsolder particles that are not used for forming the solder layer 215 arecaptured on the electrode 210 for forming the dummy bump, thereby beingprevented from outflowing toward the outside.

Incidentally, the electrode 210 for forming the dummy bump is notnecessarily provided in the case where the solder particles are notscattered and there occurs no problem even when the solder particles arescattered. The configuration thereof in the case of not providing theelectrode 210 is the flip chip mounted body 200 shown in FIG. 2.

The resin 217 in the resin composition 212 can be squeezed out in smallamount in the formation process of the dummy bump 214. Thus, afteralmost all of the gasified convection additive has passed through theexhaust pipe 204 toward the outside, the resin whose viscosity isdecreased temporarily by the heating penetrates the holes of the poroussheet 205 by a capillary phenomenon so as to fill the holes. Thereby,the resin 217 that has penetrated the holes in the porous sheet 205closes the holes of the porous sheet 205 being cured so as to preventthe intrusion of humidity and the like from the outside.

Moreover, the resin 217 after being cured fixes the semiconductor chip206 and the circuit substrate 213, and the resin 217 squeezed out fromthe dummy bump 214 adheres the peripheral edge part of the porous sheet205 that is folded to have the box shape 209 with the circuit board 213so as to fix them.

According to Embodiment 1 of the present invention, the connectionterminal of the circuit board and the electrode terminal of thesemiconductor chip can be connected reliably by the self-assembledsolder layer.

Moreover, the interval between the circuit board and the semiconductorchip can be maintained to be constant and uniform by the porous sheetthat is deformed to have the box shape.

Moreover, since the scattering of the solder particles is suppressed bythe electrode on which the dummy bump surrounding the semiconductor chipis formed, there is no influence on the outside by the scattering of thesolder particles. As a result, the circuit board with excellent quality,which is not likely to generate a contact or a short circuit between thesemiconductor chips, can be achieved.

Moreover, since the porous sheet finally has a configuration in whichhumidity and the like are not likely to pass through, the weatherresistance of the semiconductor chip is improved, so that the effects ofimproving the reliability and enabling the long term use can beachieved.

Embodiment 2

FIGS. 4A to 4D are process views schematically explaining a flip chipmounted body and a flip chip mounting method according to Embodiment 2of the present invention. It should be noted that the elements in FIGS.4A to 4D that are the same as those in FIGS. 3 to E will be denoted bythe same reference numerals, and the explanations thereof will beomitted.

Herein, a flip chip mounted body 300 in Embodiment 2 of the presentinvention adopts a mounting method that is different from that of theflip chip mounted body 250 of Embodiment 1, and has the sameconfiguration except for this.

Firstly, as shown in FIG. 4A, the connection terminal 211 on the circuitboard 213 and the electrode terminal 207 of the semiconductor chip 206are disposed opposing each other in advance. Then, between thesemiconductor chip 206 and the circuit board 213, the resin composition212 containing solder particles in a paste state, a convection additiveand a resin as main components is applied by using, for example, adispenser, and is intervened. Further, on the semiconductor chip 206,the porous sheet 205 is positioned with the semiconductor chip 206 andis adhered therewith.

Next, as shown in FIG. 4B, a mold 220 is lifted down so as to draw thesemiconductor chip 206 from an upper side. In this case, the mold 220preferably is heated so as to facilitate the deformation of the poroussheet 205.

Next, as shown in FIG. 4C, the porous sheet 205 is deformed by the mold220 into the box shape 209 along the outer periphery of thesemiconductor chip 206. Herein, the porous sheet 205 preferably isdeformed at a peripheral position that is slightly larger than thecircumference of the semiconductor chip 206 so as not to damage thesemiconductor chip 206.

Then, the porous sheet 205 and the semiconductor chip 206 are drawn intoan inside of the mold 220 via the suction path 203 by a suction effectby the suction tube 202. Thereby, the porous sheet 205 is deformed tohave the shape of the mold 220. Then, the mold 220 is in contact withthe surface of the circuit board 213, so that the interval between thesemiconductor chip 206 and the circuit board 213 is kept to be constant.Incidentally, this interval is a spacing so that at least the electrodeterminal of the semiconductor chip and the connection terminal of thecircuit board are not in contact with each other, and the melted solderpowders can intervene.

Further, in the state of FIG. 4C, the mold 220 or the lower surface sideof the circuit board 213 is heated by a heating means, for example, aheater (not illustrated) at a temperature ranging, for example, from220° C. to 250° C., at which the solder particles are melted and theconvection additive is boiled or evaporated so as to be changed into gas216.

By this heating, the convection additive (not illustrated) in the resincomposition 212 that is applied onto the circuit board 213 is boiled orevaporated so as to be changed into the gas 216, and the solderparticles (not illustrated) are changed into the melted solderparticles. Then, in a process in which the gas 216 passes through theholes of the porous sheet 205 that is folded to have the box shape 209and flows out through the exhaust pipe 204 toward the outside, themelted solder particles in the resin composition 212 are transferred bythe convection.

Further, the melted solder particles that have been transferred areself-assembled between the electrode terminal 207 of the semiconductorchip 206 and the connection terminal 211 of the circuit board 213 thatare disposed opposing each other and have high wettability, and aregrown.

Thereby, as shown in FIG. 4D, the solder layer 215 that electricallyconnects the electrode terminal 207 and the connection terminal 211 isformed, and the mold 220 is detached, thereby manufacturing the flipchip mounted body 300. Reference numeral 217 denotes a resin.

Moreover, the melted solder particles are self-assembled and grown alsoon the electrode 210 for forming the dummy bump so as to form the dummybump 214. By the formation of this dummy bump 214, the melted solderparticles that have not been used for forming the solder layer 215 arecaptured on the electrode 210 for forming the dummy bump, and areprevented from flowing out toward the outside.

It should be noted that it is not necessary provide the electrode 210for forming the dummy bump in the case where the solder particles arenot scattered and there occurs no problem even when the solder particlesare scattered.

As described above, according to Embodiment 2 of the present invention,the effect similar to that of Embodiment 1 can be achieved, and thelower mold is not necessary so as to enable the manufacture in thesimplified facility.

Moreover, in the case where the porous sheet is a thermoplastic resin, athermosetting resin, a nonwoven fabric or the like, the flip chipmounting can be achieved at a significantly low cost and with highproductivity.

Embodiment 3

FIGS. 5A to 5D are Process Views Schematically Explaining a flip Chipmounted body and a flip chip mounting method according to Embodiment 3of the present invention. It should be noted that the elements in FIGS.5A to 5D that are the same as those in FIGS. 3A to 3E will be denoted bythe same reference numerals, and the explanations thereof will beomitted.

Herein, a flip chip mounted body 400 in Embodiment 3 of the presentinvention is different from the flip chip mounted body 250 in Embodiment1 in the point that the porous sheet 205 has a brim 401 and a method formounting it, and other configurations except for these are common.

Firstly, as shown in FIG. 5A, the porous sheet 205 is deformed to have abox shape that is provided with the brim 401 by the upper mold 201 andthe lower mold 208 in advance.

The below description will provide an example where the brim 401 isprovided by folding the edge of the porous sheet 205 having the boxshape, but the present embodiment is not limited to this. In this case,since the semiconductor chip is not adhered to the porous sheet 205, thereliability of the semiconductor chip is not necessary to be consideredfor deforming the box shape, and conditions such as the application of apressure and the heating are not limited. Thus, in the case where theporous sheet 205 is made of a material that is hardly deformed by heatsuch as a foam metal, Embodiment 3 of the present invention can be moreeffective. Further, by using a magnetic material such as nickel and ironfor the foam metal, the generation of noises from the mountedsemiconductor chip can be prevented, and a shield effect for preventingthe noises from the outside can be obtained.

Next, as shown in FIG. 5B, in a state where the lower mold 208 isdetached and the porous sheet 205 is drawn, the upper mold 201 isreplaced with a position where the electrode terminal 207 of thesemiconductor chip 206 and the connection terminal 211 of the circuitboard 213 are disposed opposing each other. At this time, between thesemiconductor chip 206 and the circuit board 213, the resin composition212 that contains solder particles in a slurry state, a convectionadditive and a resin as main components is applied by using, forexample, a dispenser, and is interposed.

Moreover, when the porous sheet 205 with the box shape having the brim401 is pressurized via the semiconductor chip 206, the resin composition212 in the slurry state preferably is supplied slightly abundantly so asto be expanded to the outside slightly. As a result, as shown in FIG.5C, the porous sheet 205 is pressurized via the semiconductor chip 206,so that the inside of the porous sheet 205 with the box shape having thebrim 401 is filled with the resin composition 212 in the slurry state.Moreover, at this time, the semiconductor chip 206 is drawn by theporous sheet 205 via the holes of the porous sheet 205. Thus, thesemiconductor chip 206 and the circuit board 213 oppose each other at apredetermined interval by the box shape 209 of the porous sheet 205having the brim 401. Incidentally, the predetermined interval is at aspacing so that at least the electrode terminal of the semiconductorchip and the connection terminal of the circuit board are not in contactwith each other and the melted solder particles can intervene.

Next, in a state shown in FIG. 5C, the upper mold 201 or the lowersurface side of the circuit board 213 is heated by a heating means, forexample, a heater 402 at a temperature ranging, for example, from 220°C. to 250° C., at which the solder particles are melted and theconvection additive is boiled or evaporated so as to be changed into thegas 216.

According to this heating, the convection additive (not illustrated) inthe resin composition 212 that is applied onto the circuit board 213 isboiled or evaporated so as to be changed into the gas 216, and thesolder particles (not illustrated) are changed into the melted solderparticles. Then, in the process in which the gas 216 passes through theholes in the porous sheet 205 that is folded to have the box shapehaving the brim 401 and goes out through the exhaust pipe 204 toward theoutside, the melted solder particles in the resin composition 212 aretransferred by the convection.

Further, the melted solder particles that have been transferred areself-assembled between the electrode terminal 207 of the semiconductorchip 206 and the connection terminal 211 of the circuit board 213 thatare disposed opposing each other and have high wettability, and aregrown. Thereby, as shown in FIG. 5D, the solder layer 215 thatelectrically connects the electrode terminal 207 and the connectionterminal 211 is formed, and the upper mold 201 is detached, therebymanufacturing the flip chip mounted body 400 that is flip-chip-mounted.Reference numeral 217 denotes the resin.

Moreover, the melted solder particles are captured by the brim 401 ofthe porous sheet 205 having the box shape, and cannot be scatteredtoward the outside.

Further, after almost all of the gasified convection additive has passedthrough the exhaust pipe 204 toward the outside, the resin whoseviscosity is decreased temporarily by the heating penetrates the holesof the porous sheet 205 by a capillary phenomenon so as to fill theholes. Thereby, the resin that has penetrated the holes in the poroussheet 205 closes the holes of the porous sheet 205 after the curing soas to prevent the intrusion of humidity and the like from the outside.

Moreover, the resin in the resin composition after the curing fixes thesemiconductor chip 206 and the circuit board 213, and a part of theresin reaches a part of the brim 401 of the porous sheet 205 having thebox shape, adheres the porous sheet 205 and the circuit board 213 andfixes them. That is, after the resin is cooled and cured completely, thesemiconductor chip 206, the circuit board 213 and the porous sheet 205having the box shape are fixed with one another completely by thefunction of the resin.

It should be noted that, in FIG. 5, the porous sheet having the boxshape that is substantially the same as the circumference of thesemiconductor chip was described, but the present embodiment is notlimited to this. For example, similarly to Embodiment 1, the poroussheet may have a box shape that is larger than an outer shape of thesemiconductor chip.

Moreover, in the case where a connection strength between the circuitboard and an end surface of the box shape of the porous sheet is high,it is not particularly necessary to form the brim.

According to Embodiment 3 of the present invention, the electrode forforming the dummy bump that prevents the scattering of the solderparticles is not used, but the outflow of the solder particles and theresin can be prevented by the brim that is formed around the poroussheet having the box shape. Further, since the connection area with thecircuit board can be obtained due to the brim more than that in the caseof not providing the brim, as the connection between the circuit boardand the porous sheet becomes stronger, the reliability with respect tothe deformation can be increased more.

Embodiment 4

FIGS. 6A to 6D are Process Views Schematically Explaining a flip chipmounted body and a flip chip mounting method according to Embodiment 4of the present invention. It should be noted that the elements in FIGS.6A to 6D that are the same as those in FIGS. 3A to 3E will be denoted bythe same reference numerals, and the explanations thereof will beomitted.

Herein, a flip chip mounted body 500 in Embodiment 4 of the presentinvention is different from the flip chip mounted body 400 of Embodiment3 in its mounting method, and the configurations except for this are thesame.

Moreover, in Embodiment 4, the process for deforming the porous sheet205 is the same as the process of FIG. 5A showing the process ofEmbodiment 3, and thus the explanation thereof will be omitted.

Firstly, as shown in FIG. 6A, the semiconductor chip 206 is drawn byvacuum to an inside surface of the porous sheet 205 via the holes of theporous sheet 205 in advance.

Next, as shown in FIG. 6B, the resin composition 212 that contains thesolder particles in a paste state, a convection additive and a resin asmain components is applied onto the lower surface of the semiconductorchip 206 by using an applying member, for example, a dispenser. Needlessto say, the resin composition 212 may be applied onto the circuit board213. Thereafter, the upper mold 201 is set down while positioning theconnection terminal 211 of the circuit board 213 and the electrodeterminal 207 of the semiconductor chip 206.

Next, as shown in FIG. 6C, the semiconductor chip 206 and the circuitboard 213 are disposed in the porous sheet 205. At this time, theelectrode terminal 207 of the semiconductor chip 206 and the connectionterminal 211 of the circuit board 213 are positioned opposing each otherat a predetermined interval. Incidentally, the predetermined intervalmeans to be at a spacing so that at least the electrode terminal of thesemiconductor chip and the connection terminal of the circuit board arenot in contact with each other and the melted solder particles canintervene.

Then, in the state described above, the upper mold 201 or the lowersurface side of the circuit board 213 is heated by a heating means, forexample, the heater 402 at a temperature ranging, for example, from 220°C. to 250° C., at which the solder particles are melted and theconvection additive is boiled or evaporated so as to be changed into thegas 216.

According to this heating, the convection additive (not illustrated) inthe resin composition 212 that is applied onto the circuit board 213 isboiled or evaporated so as to be changed into the gas 216, and thesolder particles (not illustrated) are changed into the melted solderparticles. Then, in the process in which the gas 216 passes through theholes in the porous sheet 205 that is folded to have the box shapehaving the brim 401 and goes out through the exhaust pipe 204 toward theoutside, the melted solder particles in the resin composition 212 aretransferred by the convection.

Further, the melted solder particles that have been transferred areself-assembled between the electrode terminal 207 of the semiconductorchip 206 and the connection terminal 211 of the circuit board 213 thatare disposed opposing each other and have high wettability, and aregrown. Thereby, as shown in FIG. 6D, the solder layer 215 thatelectrically connects the electrode terminal 207 and the connectionterminal 211 is formed, and the upper mold 201 is detached, therebymanufacturing the flip chip mounted body 500 that is flip-chip-mounted.Reference numeral 217 denotes the resin.

As described above, according to Embodiment 4 of the present invention,the effect similar to those of the respective embodiments can beobtained, and the porous sheet 205 and the semiconductor chip 206 aretransferred in combination, and the leakage of the air at the time ofthe drawing by vacuum is smaller than that of Embodiment 3, therebyachieving the stable transfer.

As described above, the present invention has been described by way ofthe respective embodiments, but these descriptions do not limit thepresent invention, and various modification are possible. For example,as the resin containing the solder particles and the convectionadditive, the thermosetting resin was exemplified, but, for example,photocurable resins having flowability at a temperature higher than themelting point of the solder particles and resins using them incombination also may be used, as long as the porous sheet may betransparent with respect to light.

Moreover, in the respective embodiments of the present invention, theexample of using only one semiconductor chip was provided, but it isactually possible to dispose a plurality of the semiconductor chips onthe circuit board at the same time so as to carry out the respectiveprocesses.

Moreover, in the respective embodiments of the present invention, thebox shape of the porous sheet was described to be folded vertically, butthe shape thereof is not limited to this. For example, it may be atapered shape. Thereby, it is possible to enlarge the area of the holesof the porous sheet that allow the gas generated by the boiling or thelike of the convection additive to pass through toward the outside, andthus the curing temperature, a curing time and the like can be adjustedeasily.

Moreover, in the respective embodiments of the present invention, theexample where the circuit board side is heated was provided, but a sideof the mold for supporting the porous sheet and the semiconductor chipalso may be heated, and further, both sides may be heated.

Moreover, in the respective embodiments of the present invention, as theresin in the resin composition, a resin that contains any of epoxyresin, unsaturated polyester resin, polybutadiene resin, polyimideresin, polyamide resin and cyanate resin as a main material also can beused.

Further, in the respective embodiments of the present invention, as theconvection additive, decomposition type sodium hydrogencarbonate,ammonium metaborate, aluminum hydroxide, dawsonite, barium metaborate,butyl carbitol as a boiling-evaporation type, medium boilers and highboilers such as flux, isobutyl alcohol, xylene, isopentyl alcohol, butylacetate, tetrachlorethylene, methyl isobutyl ketone, ethyl carbitol,butyl carbitol and ethylene glycol, and the like can be used.

INDUSTRIAL APPLICABILITY

The present invention can apply a narrow pitch to flip chip mounting ofa proceeding next-generation semiconductor chip, and is useful in thefields that require flip chip mounting with excellent productivity andreliability.

1. A flip chip mounting method for disposing a semiconductor chip havinga plurality of electrode terminals so as oppose a circuit board having aplurality of connection terminals and connecting the connection terminalof the circuit board and the electrode terminal of the semiconductorchip electrically, the flip chip mounting method comprising: deforming aporous sheet so as to have a box shape covering the semiconductor chip;adhering the semiconductor chip to an inside bottom part of the poroussheet having a box shape; applying a solder resin composition thatcontains solder particles, a convection additive and a resin as maincomponents onto the circuit board or the semiconductor chip; positioningso as to dispose the porous sheet on the circuit board; heating theresin composition to a temperature at which the solder particles aremelted so as to generate gas by boiling or decomposition of theconvection additive; and connecting the connection terminal and theelectrode terminal electrically by allowing the melted solder particlesto flow in the resin composition so as to self-assemble and grow thesolder particles before the gas is released, passes through the poroussheet and is scattered.
 2. The flip chip mounting method according toclaim 1, wherein the deforming of the porous sheet comprises heating. 3.The flip chip mounting method according to claim 1, wherein the poroussheet has a box shape covering the semiconductor chip in the deformingof the periphery of the porous sheet, and a peripheral edge of anopening of the porous sheet having the box shape is in contact with thecircuit board so as to dispose the semiconductor chip and the circuitboard at a predetermined interval.
 4. The flip chip mounting methodaccording to claim 1, wherein the porous sheet covers the semiconductorchip, and has a box shape having a brim whose peripheral edge protrudesnear an opening.
 5. The flip chip mounting method according to claim 1,wherein the porous sheet has a hole that connects a front side and arear side.
 6. The flip chip mounting method according to claim 1,wherein the porous sheet is made of at least one material that has airpermeability selected from the group consisting of a thermoplasticresin, a thermosetting resin, a nonwoven fabric and a foam metal.
 7. Theflip chip mounting method according to claim 1, wherein the resincontained in the resin composition penetrates the porous sheet by theheating of the circuit board, closes the hole of the porous sheet and iscured after completion of the heating of the circuit board so as toreduce or inhibit moisture permeability.
 8. The flip chip mountingmethod according to claim 1, wherein the part around the porous sheetthat is in contact with the circuit board is contacted with the resincontained in the resin composition.
 9. The flip chip mounting methodaccording to claim 1, wherein the electrode is provided so as tosurround the connection terminal of the circuit board.
 10. The flip chipmounting method according to claim 1, wherein the electrode that isprovided so as to surround the connection terminal of the circuit boardis formed so as to be positioned inside the porous sheet that has a boxshape, and a dummy bump is formed by the heating of the circuit board.11. The flip chip mounting method according to claim 10, wherein theelectrode on which the dummy bump is formed by the heating preventspassing of the solder particles in the resin composition applied betweenthe semiconductor chips of the circuit board, and enables the passing ofthe resin.